Field of the Invention
The present invention relates to an apparatus and a method for counting a number of particles present in a compressed air, and a method of constructing a compressed-air cleaning system, and particularly to an apparatus and a method for sucking a compressed air introduced from a compressed-air passage and counting a number of particles present in the sucked compressed air, and a method of constructing a compressed-air cleaning system by using at least one removing device which removes particles from a compressed air.
Related Art Statement
Conventionally, many factories have been equipped with compressed-air operated devices and/or compressed-air jetting devices in which compressed air is used as a working medium or fluid. The compressed-air operated devices, the compressed-air jetting devices, or other compressed-air using devices are operated or driven, as being well known in the art, by the pressure energy of compressed air that is supplied thereto from a compressed-air source (e.g., air compressor) via a compressed-air supply pipeline (i.e., a compressed-air passage). However, when the compressed-air using devices are operated, the compressed air cannot be prevented from being contaminated with contaminating matter, such as lubricant used, or rust produced, in the compressed-air source and/or the compressed-air supply pipeline. If the compressed air is mixed with much of the contaminating matter, then the compressed-air using devices may malfunction or fall in disorder. In the case where the compressed-air using devices are used in a food production line, the safety of the food products may be adversely influenced.
Hence, generally, in factories equipped with compressed-air operated devices and/or compressed-air jetting devices, one or more removing devices which remove contaminating matter are provided at one or more locations on a compressed-air supply pipeline to prevent the contamination of compressed air.
However, almost all of those removing devices are ones each of which employs a filter for filtering compressed air to catch particles of contaminating matter present in the compressed air and thereby clean the compressed air, and the cleaning capability of the filter inevitably decreases as the time of use of the filter increases.
Hence, in some factories, it has been practiced that the cleanliness of compressed air is measured periodically or non-periodically, by counting a number of particles present in a compressed air flowing in a compressed-air supply pipeline, using a particle-number counting device such as a so-called particle counter which is mainly used to count a number of particles present in a clean room of each factory. Based on the measured cleanliness, the respective filters of the removing devices may be replaced with new ones, to maintain or control a high cleanliness of the compressed air.
However, a conventional particle-number counting device, such as a conventional particle counter, is designed to suck, through its suction inlet, a normal-pressure air in a clean room and count a number of particles present in the sucked air. Accordingly, if the counting device sucks a compressed air having a high pressure, it may be damaged or disordered. Even if the counting device may not be damaged or disordered, it may not count an accurate particle number, because it may suck an excessive amount of air.
In order to avoid the above-indicated problem, a pressure-resistant hollow case is employed which has a prescribed capacity and has an introduction inlet for introducing a compressed air. More specifically described, a compressed air is introduced from a compressed-air passage into the pressure-resistant case through the introduction inlet, and the pressure of the compressed air is lowered in the case. After the pressure-resistant case is filled with the compressed air whose pressure has been lowered, the compressed air in the case is sucked by the particle-number counting device, and a number of particles present in the sucked air is counted by the counting device. However, the conventional particle-number counting device employing the pressure-resistant case has some problems.
First, the pressure-resistant case employed in the conventional particle-number counting device needs a considerably large capacity for the purpose of sufficiently lowering the pressure of the compressed air introduced. Accordingly, the particle-number counting device including the pressure-resistant case is inevitably large-sized, which reduces the ease of use. Second, since the counting device can count a number of particles present in a compressed air after the air remaining in the large-sized pressure-resistant case is exchanged with the compressed air and the case is filled with the compressed air, it needs a long time before the counting device is prepared to start counting a particle number, which reduces the efficiency of operation.
Moreover, in many cases, a random number of above-indicated removing device or devices is or are provided at a random position or positions on the compressed-air supply pipeline of each factory, irrespective of how the compressed air flowing in the supply pipeline is actually contaminated. Thus, the total number of the removing devices and/or the positions where the removing devices are provided may not appropriately correspond to the actual condition of contamination of the compressed air, and accordingly the compressed air may not be effectively cleaned by the removing devices.